Guide: Multibooting UEFI on Separate Drives

[Mochimino]

Ho, that's a bummer. I was speaking about Clover because it's the only thing i know (i'm new to hackintosh).
So there's no solution to choose which system i want to boot when starting the computer? or only via the bios boot sequence?

 

[Going Bald]

Ho, that's a bummer. I was speaking about Clover because it's the only thing i know (i'm new to hackintosh).
So there's no solution to choose which system i want to boot when starting the computer? or only via the bios boot sequence?

No, you can boot Windows from the OC selection screen. It is a numbered line item selection as with Linux instead of a graphical icon as with Clover.

 

[Mochimino]

I'm not quite sure i understood correctly. What is the OC selection screen?
So basically when I will start the computer, a menu will appear and allow me to choose boot Windows or boot Mac OS?

I'm sorry for asking dumb questions, i'm still learning a lot about Hackintosh

 

[LisaAlterEgo]

I'm not quite sure i understood correctly. What is the OC selection screen?
So basically when I will start the computer, a menu will appear and allow me to choose boot Windows or boot Mac OS?

I'm sorry for asking dumb questions, i'm still learning a lot about Hackintosh

When you first configure OpenCore, the Builtin OS Picker uses a simple text-based interface
which, by default, shows the OS options, the recovery options, and installed tools like OpenShell.
You can set the default system to boot by entering its index or arrowing up/down to the one
you want and hitting enter. If you hit the space bar, you may get an extended menu that
includes tools like Clear NVRAM.

Once you have OpenCore working, starting with 0.5.7 it includes a graphic External OS picker
called OpenCanopy. Like Clover, it shows graphic images corresponding to each choice, and
has a text label under each one. It is in its infancy, and doesn't offer many options or themes
yet. You have to change some settings in your config file to invoke it. See the Configuration
manual in the standard Docs folder and search for OpenCanopy.

 

[jefftr66]

Process goes like this:
- boot Windows installer USB
- at first screen press Shift+F10 to get command prompt (hit enter after each line to type)
- type: diskpart
- type: list disk (so you're certain of the disk you're working with, say it is disk 0)
- type: select disk 0
- type: clean (don't blame me if you don't know what this does - hope there was nothing on that drive you wanted to save)
- type: convert gpt
- type: create partition efi size=200
- type: format quick fs=fat32 label="EFI"
- type: exit
- type: exit

Well my dual boot system is completely f$#^ed at this point - Win disk won't even boot, can't boot to the Mac side and even newly created Catalina USBs won't boot. Trying to reinstall Win on same drive it was on before using the above method and keep getting the error saying can't install on a gpt....

 

[LisaAlterEgo]

Well my dual boot system is completely f$#^ed at this point - Win disk won't even boot, can't boot to the Mac side and even newly created Catalina USBs won't boot. Trying to reinstall Win on same drive it was on before using the above method and keep getting the error saying can't install on a gpt....

Was your Windows installation USB formatted as GPT?

Windows assumes MBR media is for a legacy install, and GPT media is for a UEFI install

 

[jefftr66]

Yes, this can be a problem with Windows installer if other drives are connected. Next time make sure the Windows drive is connected to P0 in UEFI/BIOS or is connected to the first port in the default drive order list.

Only drive connected other than USB installer

 

[jefftr66]

Was your Windows installation USB formatted as GPT?

Windows assumes MBR media is for a legacy install, and GPT media is for a UEFI install

I don't recall but just created it recently and installed Win previously on this same drive. I created it on a Win machine

 

[Going Bald]

I don't recall but just created it recently and installed Win previously on this same drive. I created it on a Win machine

If your installer is giving you an error that it cannot install on a GPT disk then you only got the legacy mode installer. Since you have a Windows PC available use the Win10 media creation tool.
Win10 Install USB tool

 

[LisaAlterEgo]

Yes I agree. Before you start the Win10 media creation tool,
format your USB as fat format with a GUID partition map
in DiskUtil. I find the media creation tool sometimes fails
when your run it off your Win10 hard drive, and works better
if you move it onto your USB before you start it.